Lecture 6: Hearing Loss

Question 1

What are the 4 goals of evaluating potential hearing loss?

Answer 1

1. Nature of impairment
2. Severity of impairment
3. Anatomy of impairment
4. Etiology

Question 2

What are the two main types of hearing loss?

Answer 2

• Conductive
• Sensorineural

Question 3

When is hearing loss typically screened for?

Answer 3

• Birth
• Kindergarten
• Pre-employment/military physicals

Question 4

When is an otoacoustic emission (OAE) test performed?

Answer 4

At birth to check for inner ear function.

Question 5

Describe an otoacoustic emission test.

Answer 5

• Provider places a small earphone in the ear.
• Earphone plays a sound that should echo within the ear canal.
• Ear should send back in an echo

Can be performed while baby is sleeping, very quick.

Question 6

What is an auditory brainstem response test? (ABR)

Answer 6

• Electrodes placed on forehead, and earphone in ears.
• Sound send through earphones, while the patch monitors brain function/response.
• Can check for abnormal sensorineural development.

Question 7

If an infant fails a hearing screening, what is the protocol?

Answer 7

Need an EENT referral if the infant cannot pass a hearing test by the age of 3 months.

Question 8

What signs might suggest that a baby has hearing loss?

Answer 8

• Not being startled by loud sounds
• Not turning towards a sound after 6mo
• Not saying single words like mama or dada by 1 year old.
• Turns head if sees you, but not if you only call out name.
• Seems to hear some sounds but not others.

Question 9

How do we treat a child that has abnormal hearing screenings?

Answer 9

Visual reinforcement audiometry (VRA)

Must be 6m to 2y.

Question 10

What is a VRA test?

Answer 10

• Patient sits in a booth while distracted.
• Patient trained to look towards the sound source.
• Rewarded if they look properly.

Question 11

What is a conditioned play audiometry test? (CPA)

Answer 11

• Child performs an activity when a sound is heard.

2-5y old

Question 12

What is a pure tone audiogram?

Answer 12

Test to see what a person’s hearing range is.
Tests decibels a patient can hear at certain frequencies.

Question 13

How do we read an audiogram?

Answer 13

Y axis: intensity of sound in decibels.
X axis: pitch/frequency of sound.

Question 14

What kind of sounds are at the top of an audiogram? Bottom?

Answer 14

Top: Whispers
Bottom: Jackhammer

Question 15

What are the two types of conduction an audiogram can measure?

Answer 15

• Air conduction hearing using headphones.
• Bone conduction hearing using mastoid stimulators.

Question 16

How do you read an audiogram?

Answer 16

Each frequency is plotted based on what decibel the patient could hear it at. Both ears are tested, generating a graph, which is then compared to a standard.

Question 17

What is normal hearing range?

Answer 17

250-6000 Hz
-10 to 25 decibels.

0 decibels is the softest sound an average person can hear. Hearing something like -5 decibels on an audiogram just means you have very good hearing.

Question 18

How many decibels different is profound hearing loss from regular?

Answer 18

Nearly 100 decibels less than the average.
AKA you need a sound at 100 decibels to hear it.

Question 19

What is a tympanogram?

Answer 19

Measures mobility/compliance of the tympanic membrane and the small bones in the middle ear.

Question 20

What are the 3 types of tympanograms and what do they represent?

Answer 20

• Type A: normal
• Type B: Abnormal finding, no compliance
• Type C: Abnormal finding, eustachian tube dysfunction.

Question 21

What curves do each tympanogram type generate?

Answer 21

Question 22

What does a Type A tympanogram indicate?

Answer 22

• Normal middle ear system without fluid and normal conduction.
• Maximal peak compliance (at 0 Pa)

Question 23

What does a type B tympanogram indicate?

Answer 23

• No peak, non-mobile.
• Suggests severely restricted middle ear system.
• Often consistent with OM.
• Consistent with a middle ear pathology, such as effusion or perforation.

Question 24

What does a type C tympanogram indicate?

Answer 24

• Indicator of eustachian tube dysfunction.
• Negative pressure in middle ear space, consistent with middle ear infection or cold-eustachian tube dysfunction.
• Consistent with a sinus, allergy, or end stages of a cold.
• Presents with an early peak.

Question 25

What is Conductive hearing loss? What tests do we run?

Answer 25

When sound does not conduct efficiently through the outer ear canal to the tympanic membrane and ossicles, or middle ear. Rinne Test: BC > AC Weber test: Lateralized to defective ear. | Correct medically or surgically.

Question 26

What is sensorineural hearing loss? What tests do we run?

Answer 26

Damage to inner ear/cochlea or nerve pathways. Loss of hearing higher pitched sounds. Weber test: Lateralization to good ear Rinne Test: AC > BC (but they stop hearing it really early. You can probably hear it as the tester still.) | Most common type of PERMANENT loss. Difficult to correct.

Question 27

What are some examples of autosomal syndromes that cause hearing loss?

Answer 27

* Treacher Collins syndrome * Crouzon syndrome

Question 28

What is an example of an autosomal recessive syndrome that causes hearing loss?

Answer 28

Usher Syndrome

Question 29

What is an example of a X-linked syndrome that causes hearing loss?

Answer 29

Alport syndrome. airport = LAX (LINKED X)

Question 30

What are the other hereditary causes of hearing loss?

Answer 30

* TORCH infections * RH factor incompatibility * Prematurity * Anoxia * Hyperbilirubinemia

Question 31

What are the TORCH infections?

Answer 31

* Toxoplasma Gondii * Other (Syphilis, Parvo B19, VZV, Listeria) * Rubella * CMV * HSV2

Question 32

What are the main/common ototoxic drugs?

Answer 32

* ASA * Anti-malarials/tonic water * LASIX * Gentamicin/tobramycin * Erythromycin * Cisplantin/Carboplantin * Mercury and Lead

Question 33

What is the mnemonic for hearing loss drugs?

Answer 33

Medications Neglected Can Cause Loss Auditory-Vestibular System * Malaria drugs: Quinine or Macrolide: erythromycin * NSAID * Cisplatin/Carboplatin * Loop diuretics: Furosemide and ethacrynic acid * Aminoglycosides: gentamicin/tobramycin * Vancomycin/vincristine * Salicyclic acid: ASA

Question 34

What is otosclerosis?

Answer 34

* Disease of the ossicular chain in which the stapes affixes to the oval window. * Presents as conductive hearing loss. * It is an inherited, autosomal dominant disease!!

Question 35

How does otosclerosis typically present?

Answer 35

* Progressive unilateral/bilateral conductive hearing loss. * Improved hearing with BKG noise. * Tinnitus * Weber test should lateralize to defective ear

Question 36

How is otosclerosis treated?

Answer 36

Stapedectomy or hearing aid if sensorineural loss has occurred.

Question 37

What is a schwartz sign?

Answer 37

Red blush of the tympanic membrane over the promontory, often suggestive of otosclerosis.

Question 38

What is presbycusis?

Answer 38

Age-related hearing loss.

Question 39

How does presbycusis present?

Answer 39

* Progressive BILATERAL symmetrical sensorineural hearing loss. * Most notable at high frequencies * MOST SEVERE in males and often confused with noise-induced hearing loss.

Question 40

What parts of the ear are generally affected in presbycusis?

Answer 40

Cochlea and ossicles.

Question 41

What is the treatment for presbycusis?

Answer 41

* Hearing aids (common) * Cochlear implants (severe) * OTC CoQ10 (maybe)

Question 42

What is an acoustic neuroma/vestibular schwannoma?

Answer 42

BENIGN tumor of the schwann cells (myelin forming) that occurs on CN8

Question 43

How does an acoustic neuroma present?

Answer 43

* Unilateral, sensorineural hearing loss. * Usually only affects CN8. * Dizziness/balance problems.

Question 44

How is an acoustic neuroma diagnosed? Treated?

Answer 44

MRI to locate it. Treatment is either monitoring or radiation/surgery.

Question 45

What is the pathophysiology behind noise-induced hearing loss? (NHL)

Answer 45

Permanent hearing impairment due to hair cell damage/death.

Question 46

How loud do sounds need to be to cause NHL?

Answer 46

85+ decibels (lawnmower minimum)

Question 47

What sound range does NHL ruin?

Answer 47

Bilateral hearing of 2000-4000 Hz?

Question 48

How should we approach treatment of hearing loss in general?

Answer 48

* If due to cerumen impact or OM, treat there. * If not easily remediable, refer to EENT since it may require time-sensitive treatment like corticosteroids.

Question 49

When is routine auditory screening recommended?

Answer 49

* 65+ * Adults with previous exposure to injurious noise levels.

Question 50

Where are the 4 types of hearing aids placed?

Answer 50

* Completely in the canal * In the canal * In the ear * Behind the ear

Question 51

What is the gold standard for auditory rehabilitation of advanced sensorineural hearing loss? (SNHL)

Answer 51

Cochlear implant

Question 52

What is a cochlear implant?

Answer 52

* External microphone and speech processor under ear. * Receiver underneath temporalis muscle. * Internal receiver in the cochlea.